French hitman Lucien Bellon (Jean-Louis Trintignant ) has been hired by mobsters to kill Victor (Ted de Corsia), a rival mobster. Bellon goes to Victor's home, in Los Angeles, and shoots him point-blank. Bellon's luggage and passport are stolen. Meanwhile, on television, news accounts of the murder allude to the police seeking not a French killer but an American one. Bellon stays in Los Angeles to discover the truth. Apparently, another hit man named Lenny (Roy Scheider) has been hired to kill Bellon. Along the way, Bellon encounters a beautiful woman named Nancy (Ann-Margaret), who offers to help. As he attempts to save his own life, Bellon hijacks a car and holds a woman (Georgia Engel) and her son hostage.